If anyone had wandered along to the Maker Faire in the Elephant and Castle area of London (yes, it's really real; no, there are neither castles nor freely roaming elephants but both would be a vast improvement) on Saturday they would have found me, and the London division of Team Triggertrap, asking people if they wouldn't mind awfully screaming at the top of their lungs for us. Seriously.

You see, we'd set up the Triggertrap ScreamGrab studio because we reckoned that people summoning the exhaustive energy to scream like bellows, and then releasing it in one extended Aiouuuuuuu! would make for fantastic portraiture. And it would give Triggertrap with the sound threshold set to Very Loud Indeed™ a rather good workout. We weren't wrong!

Inspired? Want to know how we did it, so that you can give it a go yourselves? Read on!

The basics

At the least, what you need to do is to get an audio trigger that will take a photo when the volume hits a certain level, and a camera. In our case, we decided to use the Triggertrap Mobile app, but we discovered to our horror that the app itself was way too sensitive: Even with the sensitivity threshold all the way to the top, you didn’t really have to put your back into the scream to trigger the camera (in fact, speaking normally was loud enough to snap a shot). Uh-oh.

In the Android version of the app, there’s a separate slider for sensitivity, but we don’t have that level of control over the iOS app (and I did want to use the iPod Touch I had brought along, so that I wouldn’t have to tie up my phone all day).

After a spot of last-minute panicking, we discovered that there was a very simple, and delightfully low-tech solution to this: I simply stuck a small piece of packaging tape over the microphone on the iPod Touch. Hacky? Well, yes, but who cares – it did the trick!

With the tape in place, we were able to use the sensitivity slider to fine-adjust the triggering threshold. Perfect for what we were trying to do!

In theory, with the app configured and hooked up to the camera using a connection kit, that’s all you need to get the photo. Stick it on a tripod, and you’re good to go – really, everything else is showmanship. But to turn this into a far more fun experience, for us and for our sacrificial victims, we turned it into much more of a show.

Tripodclamps clamp to hold the iPod Touch in place (so that your screamers can see how loud they need to scream)

Canon ST-E2 flash trigger

2x Canon Speedlite 580EX II flashes

2x light stands

2x white umbrellas

What I did

Let's start with the lighting: I added a Canon ST-E2 infra-red flash transmitter to the camera’s hotshoe, and I set up a couple of Canon EX580 II flashes on super-cheap lighting stands with umbrellas. I fired the flashes on manual output (1/16 each), then set up the camera in manual exposure (1/180 second and f/10, ISO 640) and manual focus. This meant that all the shots were completely repeatable, and I wouldn’t have to make any adjustments throughout the day.

In fact, if it hadn’t been for people being different heights, there wouldn’t have been any reason to touch the set-up at all: even the batteries in the flashes, the flash transmitter, and the camera, lasted all day long. Impressive stuff – but then, battery consumption was the chief reason why I only set the flashes to 1/16 output – in my experience, in modern cameras, you may as well let the ISO do the work, and give your flashguns a break.

Finally, I wanted to ensure that the iPod Touch was clearly visible, so people would be able to see the black ‘needle’ move on the app – so they knew how loud they had to shout to trigger the camera. To achieve that, I used a Tripodclamps clamp. It’s simple: It bolts to the tripod, then squeezes the smartphone firmly to hold it in place. It looks good, and it makes it easy to demo the device, too, which is a bonus.

Someone check for the Four Horsemen of Apocalyspe - I shot in JPEG!

I should also mention at this point that the camera was shooting JPEGs rather than in RAW. The Canon 6D shoots enormous RAW files, and since I had a fully controllable lighting situation, I didn’t expect I’d need to do a lot of adjusting the images. More importantly, the JPEGs are much much faster to download via the tethered connection, faster to process in Lighroom, and it meant that my poor little MacBook Air didn’t slump to its knees. Having said all that, I do generally recommend shooting in Raw. Here is why, and I also wrote an article about why this particular situation (controllable light, need for speed) is an exception where JPEG is acceptable. Because, yes, I’m an insufferable nerd about this sort of stuff.

Turning it into a show

To show off the images, I decided I had to shoot ‘tethered’. I was in luck; my Canon camera comes with a piece of software called EOS Utility, which enables tethered shooting. In this case, I hooked up a27″ monitor to my MacBook Air. I made sure that all photos that were taken were shown on the audience-facing big screen as soon they were shot. Great for instant gratification – even the most reluctant screamers giggled their heads off when they saw their mugs on the big screen.

Instant publishing

I anticipated (correctly) that people would want a copy of their photos – but how do you go about doing that? Quite a few people used Instagram and took a photo of their photo on the big monitor, but obviously we wanted something a little bit better than that. So, I devised a workflow.

I was running Lightroom 4, using the ‘auto import’ feature. In this way, the photos would be downloaded by the Canon EOS Utility to a folder, and Lightroom 4 would automatically import them from that folder into a library. The import script applied a preset to the image (white-balance, some vignetting, some extra contrast and some colour effects to make the photos pop out more). It also applied a description and title to the images, so it would be as quick as possible to publish them online.

From there, I only did one edit to each photo: A quick crop. This was necessary because we didn’t have a lot of time to frame people properly, and besides, a lot of people either jumped or hunched over as they were howling at the camera, so the framing was almost always off anyway.

After cropping, we just dragged the photo to the Flickr publishing tool within Lightroom, and hit the ‘publish’ button. With one person manning the computer, that meant that from squeal to Flickr, it could take as little as a minute or so, including the processing, resizing, and uploading.

We also had an IFTTT set-up, so that we could auto-tweet our ScreamGrabs. Except that Twitter sent us to Twitter Jail for too many tweets!

Other ideas?

It would really have been awesome if we could have had a printer there, and printed out people’s ScreamGrabs as they were taken – but we didn’t really know how many people to expect, and we only had two people at our little stand at any time, so I suppose we wouldn’t really have had time to deal with the logistics of printing anyway — but it would have been amazingly good fun, so perhaps that’s something we’ll do next time.

The other idea that came up, was that perhaps we should have been recording people’s screams! Playing the screams, along with a slide-show of all the photos, would have been a fantastic project, I think – but it didn’t come up as an idea until someone mentioned it to us about half-way through the day. Again, I have no idea how you’d deal with the logistics of matching up the sounds to the pictures… But it would have been great.